Home > Progesterone (Molecule of the Month for April 2006 )
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C21 H30 O2
Progesterone is a hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species. Progesterone belongs to a class of hormones called progestagens, and is the major naturally occurring human progestagen. Progesterone, like all other steroid hormones, is synthesized from cholesterol.
Progesterone is produced in the adrenal glands, the gonads, the brain, and, during pregnancy, in the placenta (which can produce placenta produces about 250 mg progesterone/day). In women, progesterone levels are low during the preovulatory phase of the menstrual cycle, rise after ovulation, and are elevated during the luteal phase. Progesterone levels are low in children, men, and postmenopausal women.
Progesterone's reproductive function serves to convert the endometrium to its secretory stage to prepare the uterus for implantation. If pregnancy does not occur, progesterone levels will decrease leading to menstruation in the human. Normal menstrual bleeding is a progesterone withdrawal bleeding. During implantation and gestation, progesterone appears to decrease the maternal immune response to allow for the acceptance of the pregnancy. Progesterone decreases contractility of the uterine musculature.
Formal Chemical Name (IUPAC)
Update by Karl Harrison
(Molecule of the Month for April 2006 )